CHAP. XXI NEW ZEALAND 479 



were to become joined together, we should have a large 

 number of species of cassowary (perhaps several more tlian 

 are yet discovered) in one land area. If now this land 

 were gradually to be submerged, leaving a central elevated 

 region, the different species would become crowded together 

 in this portion just as the moas and kiwis were in New 

 Zealand. But we also require, at some remote epoch, a more 

 or less complete union of the islands now inhabited by the 

 separate species of cassowaries, in order that the common 

 ancestral form which afterwards became modified into these 

 species, could have reached the places where they are now 

 found ; and this gives us an idea of the complete series of 

 changes through which New Zealand is believed to have 

 passed in order to bring about its abnormally dense popula- 

 tion of wingless birds. First, we must suppose a land connec- 

 tion with some country inhabited by struthious birds, from 

 which the ancestral forms might be derived ; secondly, a 

 separation into many considerable islands, in which the 

 various distinct species might become differentiated ; 

 thirdly, an elevation bringing about the union of these 

 islands to unite the distinct species in one area; and 

 fourthly, a subsidence of a large part of the area, leav- 

 ing the present islands with the various species crowded 

 together. 



If New Zealand has really gone through such a series of 

 changes as here suggested, some proofs of it might perhaps 

 be obtained in the outlying islands which were once, pre- 

 sumably, joined with it. And this gives great importance 

 to the statement of the aborigines of the Chatham Islands, 

 that the Apteryx formerly lived there but was exterminated 

 about 1835. It is to be hoped that some search will be 

 made here and also in Norfolk Island, in both of which it 

 is not improbable remains either of Apteryx or Dinornis 

 might be discovered. 



So far we find nothing to object to in the speculations 

 of Captain Hutton, with which, on the contrary, we almost 

 wholly concur ; but we cannot follow him when he goes on 

 to suggest an Antarctic continent uniting New Zealand and 

 Australia with South America, and probably also with 

 South Africa, in order to explain the existing distribution 



